2. Body Fluid Compartments

• What are the two main compartments of body fluid?

  Extracellular fluid and intracellular fluid
• How is extracellular fluid divided?

  Into interstitial fluid and blood plasma
• What is transcellular fluid?

  Fluid in specialized compartments like synovial fluid
• What types of spaces does transcellular fluid include?

  Synovial, peritoneal, pericardial, and intraocular spaces
• How much total fluid do transcellular fluids constitute?

  About 1 to 2 liters
• What is the total body water percentage in a 70-kilogram adult man?

  About 60 percent of body weight
• If a 70-kilogram adult man has 60% body water, how many liters is that?

  About 42 liters
• What factors influence the percentage of total body water?

  Age, gender, and degree of obesity
• How does aging affect total body water percentage?

  It gradually decreases due to increased body fat
• What is the average total body water percentage for women?

  About 50 percent of body weight
• What is the total body water percentage in premature and newborn babies?

  Ranges from 70 to 75 percent of body weight
• Why should we consider variations in body fluid compartments?

  Due to differences in age, gender, and body fat
• What is the average body weight for men older than 20 years in the U.S.?

  Approximately 86.4 kg
• What is the average body weight for women older than 20 years in the U.S.?

  Approximately 74.1 kg
• How much of the total body fluid is intracellular fluid in an average person?

  About 28 liters of the total 42 liters
• What percentage of total body weight does intracellular fluid constitute?

  About 40 percent of total body weight
• What are the major body fluid compartments and their characteristics?

  • Extracellular fluid:
  • Divided into interstitial fluid and blood plasma
  • Intracellular fluid:
  • About 28 liters in 100 trillion cells
  • Constitutes about 40% of total body weight
  • Transcellular fluid:
  • Includes synovial, peritoneal, pericardial, and intraocular fluids
  • Constitutes about 1 to 2 liters
• What does the fluid of each cell contain?

  Different constituents in individual mixtures
• How do the concentrations of substances in cell fluids compare across different cells?

  They are similar from one cell to another
• What is the significance of the similarity in cell fluid composition across different animals?

  It indicates a common fluid compartment
• What is the collective term for all fluids outside the cells?

  Extracellular fluid
• What percentage of body weight do extracellular fluids account for?

  About 20 percent
• How much extracellular fluid is present in a 70-kilogram man?

  About 14 liters
• What are the two largest compartments of extracellular fluid?

  Interstitial fluid and plasma
• How much interstitial fluid is present in the extracellular fluid?

  About 11 liters
• What fraction of extracellular fluid does plasma make up?

  Almost one fourth
• What is plasma in relation to blood?

  It is the noncellular part of blood
• How does plasma exchange substances with interstitial fluid?

  Through the pores of capillary membranes
• What is the permeability of capillary pores to solutes?

  Highly permeable to almost all solutes
• How do the compositions of plasma and interstitial fluids compare?

  They are similar except for proteins
• What does blood contain in terms of fluid compartments?

  Extracellular fluid and intracellular fluid
• Why is blood considered a separate fluid compartment?

  It is contained in its own chamber
• What is the average blood volume of adults?

  About 5 liters
• What percentage of blood is plasma?

  About 60 percent
• What percentage of blood consists of red blood cells?

  About 40 percent
• How can blood volume percentages vary among individuals?

  Due to gender, weight, and other factors
• What is hematocrit?

  Fraction of blood composed of red blood cells
• How is hematocrit determined?

  By centrifuging blood in a hematocrit tube
• What happens to plasma during the hematocrit measurement?

  About 3 to 4 percent remains entrapped
• What is the normal hematocrit value in men?

  About 0.40